drm/amdgpu: Add NULL check for asic_funcs

If driver load fails too early, asic_funcs pointer remains unassigned.
Add NULL check to sanitize unwind path.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 582bf7c)
Cc: stable@vger.kernel.org

Author: Lijo Lazar

drivers/gpu/drm/amd/amdgpu/amdgpu_nbio.c

@@ -55,7 +55,8 @@ u64 amdgpu_nbio_get_pcie_replay_count(struct amdgpu_device *adev)
 
 bool amdgpu_nbio_is_replay_cnt_supported(struct amdgpu_device *adev)
 {
-	if (amdgpu_sriov_vf(adev) || !adev->asic_funcs->get_pcie_replay_count ||
+	if (amdgpu_sriov_vf(adev) || !adev->asic_funcs ||
+	    !adev->asic_funcs->get_pcie_replay_count ||
 	    (!adev->nbio.funcs || !adev->nbio.funcs->get_pcie_replay_count))
 		return false;